Herbicidal compositions of acifluorfen or salts thereof and citrates

Abstract

Compositions comprising acifluorfen or one of its agronomically acceptable salts and a citrate salt, in a weight amount greater than the acifluorfen, exhibit enhanced herbicidal activity, particularly against velvetleaf.

What is claimed is: 
     
       1. A herbicidal composition comprising (a) a herbicide selected from the group consisting of acifluorfen and an agronomically acceptable salt thereof and (b) a citrate selected from the group consisting of alkali metal, alkaline earth metal and ammonium citrates wherein the citrate is present in a greater weight amount than the herbicide. 
     
     
       2. The herbicidal composition of claim 1 wherein the herbicide is selected from the group consisting of sodium, potassium and amine acifluorfens. 
     
     
       3. The composition of claim 1 wherein the citrate is selected from the group consisting of ammonium citrates, sodium citrates and potassium citrates. 
     
     
       4. The composition of claim 3 wherein the citrate is an ammonium citrate. 
     
     
       5. The composition of claim 3 wherein the ratio of herbicide to citrate is from about 1:1 to about 1:35. 
     
     
       6. A herbicidal composition comprising (a) sodium acifluorfen and (b) a citrate selected from the group consisting of ammonium citrates, sodium citrates and potassium citrates wherein the citrate is present in a greater weight amount than the sodium acifluorfen. 
     
     
       7. The composition of claim 6 wherein component (b) is an ammonium citrate and the ratio of sodium acifluorfen to the citrate is from about 1:1 to about 1:35. 
     
     
       8. The composition of claim 6 wherein the ratio of sodium acifluorfen to the citrate is from about 1:1 to about 1:16. 
     
     
       9. A method for enhancing the herbicidal activity of acifluorfen or one of its agronomically acceptable salts in a crop locus comprising applying to the crop locus a composition comprising (a) acifluorfen or one of its agronomically acceptable salts and (b) a water soluble citrate selected from the group consisting of alkali metal, alkaline earth metal and ammonium citrates wherein the citrate is present in a greater weight amount than the acifluorfen. 
     
     
       10. The method of claim 9 wherein the ratio of acifluorfen or one of its agronomically acceptable salts to component (b) is from about 1:1 to about 1:35. 
     
     
       11. The method of claim 10 wherein the acifluorfen is sodium acifluorfen. 
     
     
       12. The method of claim 10 wherein the acifluorfen is applied in an amount of from about 0.1 to about 1.1 kilograms per hectare and the citrate is applied in an amount of from about 1.0 to about 4.5 kilograms per hectare. 
     
     
       13. The method of claim 11 wherein the citrate is selected from the group consisting of ammonium citrates, sodium citrates and potassium citrates. 
     
     
       14. The method of claim 13 wherein the citrate is an ammonium citrate. 
     
     
       15. The method of claim 14 wherein the citrate is diammonium citrate. 
     
     
       16. A method for combating weeds in an agronomic crop comprising the improvement of postemergence application to the crop locus of a liquid form of a composition comprising (a) acifluorfen or an agronomically acceptable salt thereof and (b) a citrate selected from the group consisting of ammonium citrates, sodium citrates and potassium citrates wherein component (b) is present in a greater weight amount than component (a) and wherein the application of the composition results in an enhancement in the herbicidal activity of the acifluorfen. 
     
     
       17. The method of claim 16 wherein the acifluorfen is applied in an amount of from about 0.1 to about 1.1 kilograms per hectare and the citrate is applied in an amount of from about 1.0 to about 4.5 kilograms per hectare. 
     
     
       18. The method of claim 16 wherein the acifluorfen is applied in an amount of from about 0.13 to about 0.55 kilograms per hectare and the citrate is applied in an amount of from about 1.0 to about 2.2 kilograms per hectare.